Tetrodotoxin as a biological defense agent for puffers.

Abstract

The skin of toxic puffers (Fugu niphobles, F. vermicularis vermicularis and F. pardalis) was found to release 5-80MU of tetrodotoxin (TTX) per specimen when lightly stimulated by handling. The puffer did not release any more toxin when the handling stimuli were repeated 3-5 times at a 30 min-interval. Some of them, however, recovered to release TTX on handling stimulus when kept intact for two weeks. The cultured puffer (F. rubripes rubripes) specimens which were artificially toxified by feeding with toxic puffer livers, released TTX up to 540 MU on a single handling stimulus.From these and other results, it was strongly suggested that TTX acts as a biological defense agent in puffers.